Supporting plate



FIG. 1 is a top plan view of a supporting plate showing our new design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a right side elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a front elevation view thereof;

FIG. 6 is a rear elevation view thereof; and,

FIG. 7 is a top, left, front perspective view thereof. 

CLAIM The ornamental design for a supporting plate, as shown and described. 